In the United States, the standard showerhead has a ½ inch female NPT thread.
In the United States, the Energy Policy Act of 1992 set a limit of 2.5 gallons per minute. In 2010, the maximum permitted flow rate was reduced to 2 gallons per minute (7.6 liters per minute).
The Fed's rulings and reasoning can be examined at:
Sorry. No information on contributors is available for this page.
Copyright © 2008-2013 Sizes, Inc. All rights reserved.
Last revised: 20 January 2013.